Navigation systems of the generic type, for example, in the form of mobile navigation devices, serve for navigating the user from a starting point to a destination along a suitable route. For this purpose, the navigation system features an input device that enables the user to input operator commands, particularly location information for specifying the starting point and/or the destination. The planned route from the starting point to the destination is calculated by a route calculating unit that utilizes a road network database, in which a geographic region is described in the form of machine-readable data.
The navigation systems furthermore comprise a signal receiving unit for receiving suitable position signals. These signals may consist, in particular, of satellite signals from GPS satellites or similar satellite systems. It would also be conceivable to additionally process position signals as they are transmitted by the central control of a motor vehicle, for example, speed and acceleration signals. The navigation system then determines the current position from the received position signals by means of a position finding unit.
Lastly, the navigation system also comprises an output device for optically or acoustically outputting signals to the user. Suitable output devices consist, for example, of monitor units or loudspeaker units. In navigation systems of the generic type, the output device is suitable, in particular, for optically or acoustically outputting a simulated route preview in a simulation mode. The simulated route preview in the simulation mode serves for informing the user of the functionality of the navigation system. The user should have the option, in particular, to test the navigation system under realistic conditions prior to the purchase, particularly with real voice announcements and with real map views. The option to check the functionality of the navigation system is very important for the purchasing decision.
In known navigation systems, only the destination needs to be input in order to properly operate the navigation system in the normal mode, in order to navigate the user from a starting point to a destination. The starting point is usually set as the current position that is determined by evaluating the position signals with the aid of the position finding unit. However problems arise if the starting point is determined in this fashion in the simulation mode of known navigation systems. Navigation devices displayed in a retail store usually are unable to receive GPS signals because the satellite signals cannot penetrate the structure of the retail store. Due to the lacking satellite signals, the starting point therefore cannot be automatically determined in conventional fashion by evaluating the current position. The starting point needs to be input manually in order to also realize the simulation mode for the route simulation in instances, in which the current position is indeterminable. However, investigations have shown that the customers regularly do not input the starling point due to their inexperience, namely because this also does not correspond to the normal operating sequence when using a navigation system. This is the reason why the simulation mode is usually not activated by potential buyers. This is very disadvantageous because the purchasing decision of the user is then usually based on irrational purchasing criteria and the available functionality of the navigation system is not even tested.
In other known methods, the last known position determined with the aid of positioning means is used as the starting point. However, devices on display in retail stores usually have not yet received a last position. The definition of fixed starting points for the demonstration mode at the factory can result in undesirably long simulation routes or not be covered by the actually existing map base.